This invention relates to the vapor phase dehydration of .alpha.-alkylbenzyl alcohols and substituted analogues thereof to form styrene and substituted styrenes.
Dehydration of alcohols to their corresponding unsaturated structural compounds is well known in the art. Dehydration techniques are not now generally employed in the manufacture of styrene and many homologues thereof because standard dehydrogenation of ethylbenzene is considered to be a more economic route. In addition, styrenes produced by conventional dehydration techniques including those employing titania as the dehydration catalyst often contain enough ethylbenzene and other impurities to require extensive purification.
It is characteristic of standard dehydrogenation techniques employed in the production of styrene that fairly large quantities of unreacted ethylbenzene be present in the styrene fraction. Such quantities of ethylbenzene in the styrene fraction are substantial enough to cause loss of properties in polymers of such styrene fractions. Furthermore, due to the closeness of the boiling points of styrene and ethylbenzene, removal of ethylbenzene by distillation is expensive.
Conventional dehydration techniques for preparing styrene and substituted styrenes are not completely satisfactory in that substantial amounts of ethylbenzene and other difficult to separate impurities often remain or are produced. Such difficulties have been pointed out in prior publications such as U.S. Pat. Nos. 2,399,395 and 3,442,963.
Therefore, it would be highly desirable to provide a new, improved technique for producing styrene and substituted styrenes in high yield which contain little or no alkyl benzene impurities.